1. Field of the Invention
The present invention generally relates to an apparatus for hinging together the housings of a foldable, portable communication device such as a handheld radiotelephone, and in particular to a hinging apparatus which facilitates opening and closing of the device.
2. Prior Art
Portable radiotelephones generally have two housings joined by a type of hinge that allows the housings to fold upon one another. Many such foldable radiotelephones have most of the electronics in one housing, called the main housing, and a few electronics in the other housing, called the cover. Other such foldable radiotelephones have all the electronics in the main housing, with the cover serving only to cover a keypad and a display of the main housing. Manufacturers are constantly seeking to reduce the volume, size and weight of these portable radiotelephones. Thus, it is desirable that the hinge coupling the main housing with the cover is modularized and miniaturized. A modularized hinge device has moving parts such as a cam member, a cam follower and a spring held together in a unified structure. The structure is easily and quickly attached to the main housing and the cover during mass production. A miniaturized hinge device has as few parts as possible, with the parts being as small as practicable.
U.S. Pat. No. 6,292,980 describes a mechanism for a foldable mobile phone. The mechanism includes a cam having a concave portion, a shaft having a convex portion, and a spring which makes the concave portion tightly contact the convex portion. The cam, the shaft and the spring are received in a housing. A flip cover rotates about a main body of the mobile phone by overcoming the force of the spring, to make the concave portion rotate about the convex portion. However, a user must open the mobile phone using both hands. This makes the mobile phone awkward to utilize in situations when the user has only one hand free.
Therefore, a new hinge mechanism is desired in order to overcome the above-described shortcoming.